A cardiac arrhythmia is a condition in which the heart's normal rhythm is disrupted. Certain types of cardiac arrhythmias, such as paroxysmal atrial fibrillation, may originate from an arrhythmogenic focus in or close to the pulmonary veins. Recent studies of pulmonary vein (PV) morphology showed that there is a wide variability in, for example, PV diameters at the ostia between the position of the veins within the same patient's heart (right superior PV, left superior PV, right inferior PV, and left inferior PV). These studies also showed that the diameter and cross-sectional area of the left superior PV are gender dependent, being significantly larger in men than in women.
Many types of cardiac arrhythmia may be treated by various ablation methods, including cryoablation. Data analysis of cryotherapy procedures showed that the use of cryoballoon catheters in combination with focal or radiofrequency (RF) catheters is common. Generally speaking, the focal or RF catheters are used to access sections of the PVs at the ostia that are inaccessible using only the cryoballoon catheter or that still exhibit conduction of aberrant electrical signals after cryoballoon ablation. The average rate of using such touch-up methods for three consecutive years was about 11% (2011, 2012, and 2013).
Given the variation in PV morphology between patients of different genders and, indeed, within a single patient, means that treating arrhythmia using a one-size-fits-all cryoballoon catheter without the need for one or more touch-up procedures is nearly impossible. As the need for focal or RF catheter ablation following cryoablation poses a safety risk to the patient and increases procedure time, it is desirable to provide a cryoablation device that can be adjusted to accommodate a variety of PV morphologies, such as PV diameter, cross-sectional area, shape, etc.